ABOUT TEACHING -- #47

A Newsletter of the Center for Teaching Effectiveness
January 1995

Problem-Based Learning in Physics:

The Power of Students Teaching Students

Barbara J. DuchCenter for Teaching Effectiveness

One week you are a health care worker in the Winter Olympics at
Lilihammer. The top French ski jumper has fallen and injured his hip. What
do you tell him to do in order to minimize the forces on the sore hip?
Another week you are a traffic officer investigating an automobile accident
involving personal injuries. What measurements do you take, what data do you
need to gather, and what assumptions do you need to make in order to discover
which driver is at fault? How will you prove that you are right? You most
likely will be required to testify in court.

These are a few of the many roles played by students in my Honor's
General Physics course as they attempt to solve complex, real world problems
using physics principles. The problems developed for this class demanded that
students do several things: connect new knowledge to old; recognize what they
know and understand -- and what they don't; learn concepts thoroughly enough
so they can explain and teach in their own words.

In a traditional science class, learning tends to proceed from the
abstract to the concrete, with concepts being introduced first, followed by an
application problem. In problem-based learning (PBL), students are presented
with an interesting, relevant problem "up front", so that they can experience
for themselves the process of doing science: they proceed from the known to
the unknown in order to understand the underlying abstract principles.
Students who acquire scientific knowledge in the context in which it will be
used are more likely to retain what they learned, and apply that knowledge
appropriately (Albanese and Mitchell, 1993; Boud and Felletti, 1991).

Students worked in groups of four and learned to teach each other,
effectively communicating what they knew -- and what they didn't. They learned
to depend on each other in order to successfully solve complex problems, and
to design and carry out open-ended experiments. Research has shown that
students' achievement is enhanced when they work together in a cooperative
learning environment (Johnson, et al.,1991; Bonwell and Eisen, 1991). Use of
cooperative groups fosters the development of learning communities in the
classroom which reduces the high competitiveness and isolation of typical
science courses (Tobias, 1990 and 1992; Project Kaleidoscope, 1991).

Features of this coures

I randomly assigned the twenty-four students to six permanent groups of
four. Each individual in the group had specific responsibilities each week,
with these roles (discussion leader, recorder, reporter, focusser/accuracy
coach) rotating weekly. Each group also established a set of groundrules and
consequences under which the group functioned. Most groups adapted
groundrules of the following type: mandatory attendance at class and group
meetings; come prepared to class and group meetings, reporter must show rough
draft of problem/lab one day before assignment is due; etc. Students in their
assigned groups worked through the real world problems, teaching each other
the physics principles needed to understand the problem. Some problem sets
were assigned to the groups while some were done individually. Experiments
were also designed to be conducted in groups of four.

Real World Applications

Whenever possible, problems and experiments related the basic physics
principles to the real world -- especially biology, medicine and the human
body. For example, while a traditional physics class learns about forces and
torques using weights, bars, and pulleys, I challenged my students to discover
how those concepts could be applied to determine how to minimize force on the
injured hip of an Olympic ski jumper. They found that if the center of mass
was shifted more directly over the injured hip the forces were minimized.

While a traditional class learns about linear momentum, my students were
analyzing the description and sketch of a police automobile accident report.
And using every concept learned in the course up until that time (equations of
motions, Newton's Laws, work and energy principles and conservation of
momentum in two dimensions), the students had to make assumptions (and justify
them) in order to decide fault in the case.

Student Attitudes

Student response to various aspects of this course on final course ratings
forms was quite positive. When students were interviewed by an independent
consultant, they all responded that working in groups aided their learning.

Here are some typical comments:

Group work helped me see there's more than one way to approach a
problem.

The groups definitely help -- not only if you don't know the answer, but
if you have to explain it to others -- you really have to understand it.

Responding to the question: What did you learn that was new and meaningful to
you?

I hadn't realized how much physics actually affected the human body or
how interesting it could be.

I learned the beginnings of how to apply the knowledge that I learn in
the classroom to real life experiences. Too often, equations are
learned, but two months later it is forgotten. This class left me with
knowledge that hopefully I will retain forever.

Responding to the use of complex real world problems to initiate the learning
of physics principles, students responded:

They helped unite the concepts.

They're like a mystery that needed to be figured out - so you wanted to
finish it.

Personal Observations

Using problem-based learning, with students responsible for working and
learning together in groups, I found that attendance was almost 100%, students
were active, participating and questioning thoughout class. They continually
challenged me with questions which went beyond typical basic physics
principles. Would I return to lecturing in a traditional fashion? Not a
chance. The excitement and energy of a room of students working in groups,
teaching each other, challenging each other, and questioning each other is
what I'll always want to see in my classroom.